Answer
u = 10
Explanation:
For now we do not know what u equals, but we do know that 20/5 = 4, because 20/5 simplified is just 4 since the fraction means 20 ÷ 4. Now that we are back to the question, with 2/5; if you multiply by 10 the numerator will then be 20. And now the equation is true! Hope this helps!